Attachment for drills



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Filed July 2, 1928 is ing so as to center the bit -to and enable thespotting hole'to bedrilled Patented Nov. 17., 1931 AXEL Lll'illillAHI,l0F AURORA., ILLINOIS, TOOL COMPANY, OF CHICAGO, ILLINOIS,

ASSIGNOR T INDEPENDENT PNEUMATIC vun:Mmmm: ron DmLLs Application ledJuly 2,

rlhis invention relates to a device for use with portable power drivendrilling tools, such as pneumatic and' electric drills, for drillingspotting 3 n for pieces of hardware and other fixtures.

The invention contemplates an attachment which when applied to a drillwill automati- Y cally center thedrill bit with respect to thescrew-receiving opening in the fixture-whe m 'fastened in place andlimit theidepth to which the spotting hole may loe drilled by the blt.-

' s [a lurther object ol the invention 1s to pro-` vide'the attachmentwith a guide which enters and lis within the screw-receivingqopeni withrespectthereexactly in the center et said opening, so that thescrew-head when brought into the same will he concentric and noteccentric therewith #so to'spoil 'the appearance ot the worl'r.

l liurther object of the invention is toprovide the attachment withtelescopic parts and a stop therefor by spotting hole will be limited onone of the ae parts coming into contact with the stop.

'lhe invention consists Jnrther in the matters hereinafter described andclaimed.

lln the accompanying drawings- Fig. 'l shows an electric the attachmentof my invention; and Fie. the attachment to show its details ofconstruction. f

The portable power driven drilling tool inv Fig. 1 is in the form of anelectric drill, having secured together motor and gear case sections 1,2 and a chuck 3 at the outer end oi the gear case section and supportinga drill hit Il, as in tools of this general character. The attachment ofmy invention comprises a collar 6' which is clamped about the forwardlyextending tubular portion 5 of the gear case section 2 and which portion5 is turned up concentric with the spindle of the tool. The collar 6 isslotted on one side and is drawn tightly about the portion 5 by means ofa clamp provided on the collar at one side thereof, and a post 8 has apressed lit in said boss. The

holes for fastening screws .the spring engages the which the depth'otthe' drill provided with 2 is a vertical sectional'view throughy screw.An apertured boss 7 is.

1928. Serial No. 289,691.

post 8 has the length desired and extends forward from the boss insubstantially parallel relation to the coinciding axes of the spindleand bit 4 of the tool. 4

A. member 9, which may be in'the form of a sleeve,v has a slidingliti'on the posty 8 and is provided-on one or bothsides with anelongated slot 10, through-'which extends 'a pin or screw 11 carried byIthe post 8 to limit the sliding movement of. thefsleeve on L the post.The uppernrinner en'lfoi' loneor both of the slots 10' ishclosed.soasjto limit the outward movement ofl the islefe'vel) on the posta-ndthus prevent thesle'evefrom sliding or dropping ott o the post.' f

, A coil spring 12 is located in the sleeve 9 and entends into a chamberor recessglfwhich is provided in the outer end portion o the -post 8,as-shown inligv. Theinner end of cess and the outer endV of the springbears against the closed outer end of the Ito normally torce the sleeveoutward on the post., as shown in Fig. 2. Che outer end of the sleeve 9is provided with a recess le to receive f the adjacent end of the springl2 so as the latter central. l I

An arin 15 is provided at the outer end of the sleeve' 9, and said armextends over the center of the drill spindle. A tubular guide lisprovided at the outer end of the arm 15 and extends forward therefromconcentric with'the axis' of the drill spindle. i The guide 16 isprovided 'with a passage or loore to receive the drill bit 4 and thuspermit the latter '85 to enter the work on forcing thedrill toward the.same, as usual in drilling operations. The guide 16 may havescrew-threaded connection with the arm 15 for removability, and saidthreads may be lett-handed ones so that the guide will not 'be turnedoil the arm in the right-hand rotation of the bit 4 during a. drillingoperation. The guide 16 is provided on one side with a slot 17 whichopens into the bore of the guide to allow chips to reely pass out of theguide during a` drilling operation.

The guide 16 is made of a size and .shape to enter and fit within thescrew-receiving openings 18 in a piece of hardware or other inner 'endot said resleeve 9l Ill on the sleeve furth same, as shown in thedrawings.

To drill the spotting holes for the screws 21 in the support 20, thepiece of hardware 19 t0 be attached to the support is placed thereon inthe position it is to be fastened to the support by the screws 21. Theoperator holding the tool then inserts the guide 16 in one o thecountersunk openin s 18, and, with the outer end of the guide ttingwithin said opening, the guide centers the drill bit 4 with respectthereto. Then by pressing the tool against the iixture 19, the drill bit4. will be forced into the support 2Q with the outer surface of theplate 19, as desired for finished work. The spotting holes for the otherscrews may be drilled in the sameway, and the screw-heads penings 18 andnot eccentric thereto to spoil the finish of the work as heretofore. sthe operator presses thetool against the work in drilling the spottingholes, the post 8 and sleeve 9 slide one with respect to the otheragainst the tension of the spring 12, and 9 contacting with the boss 7er movement of the bit 4. Y 1s stopped, thereby automatically limitingthe depth of the spotting holes that may be drilled by the bit.

On withdrawing the bit 4 from the support 20, the spring 12 forces thesleeve 9 outward until it 1s contacting h he inner end of the slot 10,in which parts are normal and are set to center and be drilled.

my invention is simple operation and positive Y By means of the device,spotting holes for the screws may accurately and quickly drilled to thedepth Y desired and accurately formed in the center of thescrew-receiving openings, without any attention required on the part ofthe operator except to insert the guide 16 into the openings and pressthe tool against the work. The centering of the it and tures, such ashinges and latches for the outside of frames and doors forrefrigerators, kitchen cabinets and the like; handles, latches and thelike on sliding windows with thereto so that driven gauge the nextspotting hole to frames of wood in cars, and other attachments in suchcars, as corner pieces on seat backs, etc.

"The details of structure shown and demay be variously changed andmodiied without departing from the spirit yand scope of my invention.

I claim as -my invention:

1. A11 attachment for portable power driven drilling tools, comprising acollar t0 be clamped about the tool and having a boss at one sidethereof, a post carried by said boss, a sleeve having a sliding t onsaid post, a guide carried by said sleeve at its outer en and adapted toenter and lit within a screw-receiving opening in a piece of hardware orother lixture on applying the tool the spotting ho e for the screw bythe bit of the tool central may be drilled said opening, and a springwith respect Ato for normally moving the post, said sleeve contacting tolimit the depth of the hole drilled by the blt. l

2. An attachment `for portable power driven drilling tools, comprising acollar to be clamped about the tool and having boss at one side thereof,a post oss, a sleeve slidably mounted on said post having an elongatedslot in one side thereof, a pin carried by the post and extendingthrough the slot, a spring in said .sleeve lly moving the sleeve outwardon the post, an arm at the outer end of the sleeve and extending towardthe bit of the tool, and a guide carried by said arm at the bit andhaving a passage therethrough for the bit.

3. The combination with a drilling tool having with the boss that may berespect to said opening. means associated with said members for e sameagainst rotation and for limiting the depth of the hole that may bedrilled by the bit.

In testimony whereof I atlix my signature. AXEL LEVEDAHL. i

the sleeve outward on passenger and sleeping l

